Space Shuttle Astronauts Prepare for Spacewalk

Astronauts aboard the International Space Station (ISS) are preparing for another spacewalk later Monday to complete repairs to the outpost's power-generating solar arrays.

Two astronauts will begin their fourth spacewalk since the U.S. space shuttle Endeavour docked with the ISS on November 16. Mission controllers say they will continue lubricating and rebuilding a joint that turns solar panels to face the sun.

Astronauts began the work Saturday during a seven-hour spacewalk.

Inside the space station on Sunday, astronauts attempted to fix a newly installed system designed to recycle their urine into drinking water. The system shut down twice during testing on Friday.

The astronauts made changes to the recycler's mounting system. It appeared to run normally for a while, but began to show signs that led up to the earlier shutdowns.

The unit may have to be brought back to Earth for further troubleshooting.

Endeavour is on a 15-day mission to expand and improve the space station's living area.

The shuttle is scheduled to return to Earth November 29.

The mission coincided with the 10th anniversary of the space station, which is said to have orbited the Earth more than 57,500 times since its first component was launched in 1998.